Vent control



E. A. BOULAY VENT CONTROL Aug. 27, 1963 2 Sheets-Sheet 1 Filed Dec. 28,1961 INVENTOR. BEYDWARD A. BouLAY ATTORNEY Aug. 27, 1963 E. A. BOULAY3,101,833

VENT CONTROL Filed Dec. 28, 1961 2 Sheets-Sheet 2 lhl. :7 H 23 A\ l I FIG. 3

INVENTOR.

EDWARD A. BOULAY ATTORNEY United States Patent 3,101,838 VENT CONTROLEdward Alphonse Boulay, Concord, NH. Filed Dec. 28, 1961, Ser. No.162,852 8 Claims. (Cl. 199-32) This invention relates to a vent control,and more specifically to a vent control device for use in a slug castingmachine.

In a slug casting machine such as the Linotype or Intertype the matricesare assembled on the assembly elevator with the spacebands for the, lineof type, from which they 'are lifted and transferred to the castingelevator for presentation to the molding apparatus. The transfermechanism includes a delivery slide which is movable laterally todeliver the matrices and spaceband's to the casting elevator, and twocontrol fingers which are preset to establish the length 'of the typeline. The movement of the delivery slide is rapid and his arrested atthe end of its stroke by an air cylinder or dash pot. However, the ventof the cylinder is suficient only to prevent the buildup of pressuretherein which would prevent operation of the delivery slide, and doesnot control the abrupt halting of delivery slide motion at the end ofthe stroke. It is this abrupt stop which causes the long finger to jumpout of engagement with the line of matrices and spacebands when saidline is 'a short one and the finger stops before engagement with itsstop device. Hence some of the matrices will at times be caused to dropout of the line being transferred as the finger moves out of engagementat the end of a stroke.

It is therefore a main object of this invention to provide apparatus forthe absolute control of the motion of the delivery slide in a slugcasting machine.

It is another object to provide regulatory means for the motion of thedelivery slide wherein the control may be adjusted.

A further object is to control the motion of the delivery slide andarrest such motion incident only to conditions when such motion isexcessively rapid.

A further object of this invention is to provide a multiple stageautomatic control over the operation or the arresting cylinder in a slugcasting machine.

Another main object of this invention is to provide apparatus forcontrolling the venting of fluid pressure from a dashpot.

Other objects and advantages will become apparent from the followingdetailed specification.

In carrying out these and other objects there is provided a vent controlfor a fluid pressure cylinder comprising a casing defining a chamber incommunication with the cylinder, a primary vent from the chamber,'apiston slide in the chamber operable to open or close the primarybent, and a secondary vent opposite one end of the piston slide forcontrolling the movement of the piston slide ,in the chamber.

In the drawings: I

FIG. 1 is a fragmentary perspective view of the delivery slide apparatusof a slug casting machine and such devices incident to the operation ofthe delivery slide.

FIG. 2 is anenlarged longitudinal sectional view of a vent controlaccording to this invention, the vent being in the closed position.

FIG. 3 is an enlarged longitudinal sectional view similar to FIG. 2,showing the vent control in the open position.

FIG. 3 illustrates the delivery slide mechanism of a line castingmachine. It is to be understood that the mechanism is normally mountedin the face plate of the machine (not shown) and in position over theassembly elevator in which the matrices are conveyed from theirmagazines in response to actuation of a keyboard. The

3,101,838 Patented Aug. 27, 1963 matrices and spacebands (not shown) arethen carried by the delivery slide mechanism to the casting elevator,thence to the casting and molding mechanism of the machine. The deliveryslide comprises two line engaging fingers designated herein as the longfinger 39 and the short finger 40 which 'are assembled on the slide bar44. The fingers 39 and 40 are spaced along a notched adjusting rod 42,and a latch 43 is movable into and out of the notches in the rod 42- tolock the long finger 39 at any predetermined point along the rod 42 Theslide bar 44 is mounted for movement in a lateral direction so as to becarried by blocks 41. During the delivery stroke of the slide bar 44,the bar moves to a point where it is stopped by the stop 34, which ismounted on the face plate of the machine (not shown). A delivery lever.36 is connected to the slide bar 44 by means of link 38 for actuationof the slide bar 44. The other end of the lever 36 is connected to ashaft 35. Spring 37 is connected to the shaft 35 for turning same to actupon the lever 36.

Also connected to the shaft 35 is a link 33, the end of which isfastened to the end of a piston rod 32 of piston 31. The piston 31 isdisposed in an air cylinder 30 or dashpot. This cylinder 30 acts as aspeed arrester for the motion of the delivery slide bar.

During operation, release of the delivery slide mechanism permits thespring 37 to turn the shaft 35 and thus move lever 36 against line 38.The line 38 operates the slide bar 44 toward the stop 34, carrying acomposed line of matrices and spacebands which are held by the fingers39 and 40. It is to be understood that the composed line (not shown)will be engaged first by the short finger 40 during movement of thedelivery slide bar 44 and is thus moved into engagement with the longfinger 39, the whole thence being moved toward the viewers left. Themotion of the delivery slide is normally rapid, and it is the functionof the cylinder 30 to arrest this rapid motion by building up airpressure therein before the delivery slide reaches the stop 34. Theconventional vent in the cylinder 30 can be adjusted to permit a gradualincrease of pressure, which will not prevent the slide bar 44 fromstriking the stop 34 hard enough to cause some of the matrices to becomedislodged from the composed line. Conversely, the vent can be adjustedso as to prevent the rapid enough and efiicient motion of the slide bar44. Should the slide bar 44 not transfer properly due to the vent beingtoo small, a following line of matrices and spacebands can enter theassembly elevator before the completion of the delivery cycle. Moreover,it will be apparent that the motion of the delivery slide mechanism willbe very rapid during the initial part of the stroke until buildup ofsufiicient pressure within the cylprises a casing 11 defining a chamber12 therethrough.

An adapter 13 is fastened in one end of the casing 11 as by screwthreads, and the other end of the adapter 13 is threaded into the end ofthe cylinder 30. An inlet 14 is provided through the adapter .13 to thechamber 12. A primary vent 15 is formed through the side of the casingin communication with the chamber 12, thence in communication with theinterior of the cylinder 30. A slide valve 16 is substantially freelydisposed within the chamber .12, and is shaped to conform to the shapeof the chamber 12, being of nearly the same dimension.

In the outer end of the body 11 is disposed a knob 19 having a longthreaded shank 20. Mating threads are formed in the Wall of the chamber12 to receive the shank 20 of knob .19. A second chamber 21 is formedthrough the knob 19, and a scondary vent 22 is formed between thechamber 21 and the atmosphere. An adjusting screw 23 is disposed in theend of the chamber 21 to a point to control the size of the opening fromthe chamber 21 to the secondary vent -22.

Depending from the slide valve 16 is a small piston 17. The size andcross section of the piston 17 are complementary to that of the chamber211 formed in the knob 19, so as to form a close sliding fit of thepiston 17 in the chamber 21 similar to that of the slide valve 16 in thechamber 12. A spring 118 is disposed around the piston 17 to urge thepiston and slide valve to the viewers right in FIG. 2, which is towardthe closed position of the vent control. By a comparison of FIGS. 2 and3 it will become apparent that the knob 19 may be adjustedlongitudinally by means of its threaded shank 20 within the chamber 12to preset the distance of maximum travel of the piston 17 to the viewersleft, or toward the open position of the vent control. This adjustmentof the knob 19 controls the degree to which the slide valve 16 willuncover the primary vent 15 to permit the escape of fluid pressuretherethrough.

Adjustment of the screw 23 controls the size of the opening from thesecond chamber 21 to the secondary vent 22, thus controlling the degreeto which air or fluid pressure in the chamber 21 may be forced throughthe secondary vent 22 during movement of the piston 17 toward the left,or open position. Fluid pressure entering into the chamber 12 from theinlet 14- moves the slide valve similar to a piston, and against theurging of the spring .18.

The operation of the vent control according to this invention is as'follows: It is to be assumed that this vent control has been installedin communication with the interior of the cylinder 30 by means of theadapter 13 as shown in FIG. 1, and that all adjustments of the knob 19and the screw 23 have been made, and that the delivery slide of themachine is about to begin a new cycle of delivering a composed line ofmatrices and spacebands to the casting elevator. Thus, all pants of theapparatus are in the relative positions as shown in FIGS. 1 and 2.

As the delivery slide apparatus is released for transfer motion, thepower of spring 37 operates the lever 36 to move the slide bar; and alsooperates lever 33 and piston rod 32 of the cylinder 30. This actioncauses the piston 31 of the cylinder 30 to move upwardly, increasing thefluid pressure in the cylinder.

A slight increase in pressure in cylinder 30 is communicated through theinlet .14 to the chamber 12 in the vent control body 1 1. Due to therelatively smaller size of the chamber 12 with respect to that of thecylinder 30, only a slight movement of the piston 31 is required tooperate the vent control 10. However, due to the rapid movement of thedelivery slide by the spring 37, the buildup of pressure in chamber 12is severe, causing a quick starting movement of the slide vent .16 andpiston 17 toward the left, or open position. Since the second chamber 21is substantially smaller in size than the chamber 12, an even more rapidand severe increase of pressure occurs in the chamber 21 to arrest theinitial motion of the slide valve 16 and piston 17.

The initial arrest or slowing down of the slide valve 16 prevents anygreat escape of fluid pressure through the primary vent 15. The fluidpressure in the cylinder 30 is merely relieved to some extent byexpansion into chamber .12. Simultaneously, the gradual escape of fluidpressure through the secondary vent 22 permits the piston 17 to moveslowly to the left, also moving the slide valve 17 to slowly uncovermore of the primary vent 15. This gradual opening of the vent 15 occursin direct proportion to the increase of fluid pressure within thecylinder 30, and thus serves to provide a constantly proportionallycontrolled venting of said fluid pressure.

When the piston .17 reaches its maximum stroke to the left, as governedby the position of the knob 19 in the end of the chamber 12 of the body11; the primary vent 15 is opened to the degree required for the properventing of the cylinder 30 incident to the desired speed of the deliveryslide apparatus in delivery of a line of composed matrices andspacebands. At this time, the piston 17 and slide valve 16 are in therelative position illustrated in FIG. 3. It will be understood that thecomplete operation of the vent control 10 takes place in a very shorttime. However, the following advantages are inherent in thisimprovement:

Firstly, the vent control 10 according to this invention permits a veryrapid buildup of fluid pressure in the cylinder 30 due to the primaryvent being closed. Secondly, the rapid increase of pressure in thecylinder 30 means that the least possible movement of the delivery slidebar 44 is required to gain the necessary fluid pressure in the cylinder30 and its vent control '10 to achieve complete control over the motionof the slide bar 44. Third, the initial motion of the delivery slide bar44 may be controlled. This is achieved through the adjustment of thescrew 23 in the vent control knob 19. Fourth, the overall speed of thedelivery slide bar 44 may be precisely controlledi This is achievedthrough the adjustment of the slide valve travel by the position of theknob 19 in the end of the body 1 1,-thus regulating the size of theopening from the chamber 12 past the slide valve 16 to the primary vent.15. Fifth, the acceleration of the slide bar 44 is controlled to begradual, resulting in a gentle rather than an abrupt stop of the slidebar 44 against the stop 34 summarily, the invention contemplates animprovement to all dashpot construction involving the need for acontrolled venting of fluid pressure from a chamber or the like. Theinvention, in its broader aspects provides for the control of ventingwhere the resistance to the escape of pressure is propontional to therate of increase of the pressure. The fluid pressure does not escapethrough the movable member of the vent control, or past the movablemember; but merely travels to the member to actuate same. Because of theregulatory feature of the secondary vent, the main or primary vent iscontrolled proportional to the increase of pressure since a more severeincrease of pressure will aflect the movement of the slide valve 1 6 thesame as a gradual increase of pressure.

A preferred embodiment of the invention having been shown and described,it is to be understood that the embodiment disclosed is tor purposes ofillustration only, and the invention is to be construed in the truespirit and scope of the appended claims.

I claim:

1. A vent control for fluid pressure comprising a casing defining afirst chamber, a fluid pressure inlet into said first chamber, a primaryvent formed from said first chamber, -a slide valve slidably disposed insaid first chamber, a second chamber in communication with said firstchamber, a secondary vent from said second chamber, and a pistondepending from said slide valve and disposed in said second chamber.

2. A vent control for fluid pressure comprising a casing defining afirst chamber having formed therefrom a primary vent, a slide valveslidably disposed in said chamber for opening and closing said primaryvent, a second chamber formed axially from said first chamber, asecondary vent formed from said second chamber, and a piston dependingfrom said slide valve and being disposed in said second chamber slidablytherein, the length of said second chamber being variable.

3. A vent control according to claim 2; and a means for varying theopening from said second chamber to said secondary vent.

4. A vent control for fluid pressure comprising a casing defining afirst chamber having fiormed therefrom a primary vent, a slide valvedisposed in said first chamber, a second chamber formed from said firstchamber, and a secondary vent formed from said second chamber, a pistondepending from said slide valve and being disposed in said secondchamber, said slide valve and piston being slidable respectively in saidchambers simultaneously in response to an increase of fluid pressure insaid first chamber for opening said primary vent.

5. A vent control for fluid pressure comprising a casing defining afirst chamber having formed therefrom a primary vent, a second chamberformed from said first chamber, a secondary vent formed from said secondchamber, a slide valve disposed in said first chamber and a dependingpiston from the slide valve disposed in said second chamber, said valveand piston being slidable in said chambers, and adjustment means forvarying the opening from said second chamber to. said secondary vent.

6. A vent control for fluid pressure comprising a casing, a firstchamber defined by said casing, a primary vent formed from said firstchamber, a fluid pressure inlet formed in an end of said casing, amovable member disposed in the other end of said casing, said movablemember defining a second chamber in communication with said firstchamber, a secondary vent formed from said second chamber, adjustablemeans for varying the opening from said second chamber to said secondaryvent, a slide valve disposed in said first chamber and a dependingpiston from said slide valve and integral therewith disposed in saidsecond chamber, said slide valve and piston being movable from aposition normally closing said pri- 6 mary vent responsive to anincrease in pressure in said first chamber.

7. In a slug casting machine, the combination of a composed linedelivery slide, power means for moving the slide, and means connected tosaid power means for arresting the movement of said slide, saidarresting means comprising a dashpot and a vent control for saiddashpot; said vent control comprising a casing defining a first chamber,a primary vent formed from said first chamber, a second chamber incommunication With said first chamber, a secondary vent formed from saidsecond chamber, and a slide valve disposed in said first chamber and adepending piston from said slide valve and integral therewith disposedin said second chamber.

8. In a slug casting a machine, the combination of a composed linedelivery slide, power means for moving the slide, and means connected tosaid power means for arresting the movement of said slide, saidarresting means comprising a dashpot and a vent control for saiddashpot; said vent control including a casing defining a chamber, a ventformed from said chamber, and a slide valve slidably disposed in saidchamber, said slide valve being movable in response to an increase ofpressure in said chamber from a position normally closing said vent.

References Cited in the file of this patent UNITED STATES PATENTS

7. IN A SLUG CASTING MACHINE, THE COMBINATION OF A COMPOSED LINEDELIVERY SLIDE, POWER MEANS FOR MOVING THE SLIDE, AND MEANS CONNECTED TOSAID POWER MEANS FOR ARRESTING THE MOVEMENT OF SAID SLIDE, SAIDARRESTING MEANS COMPRISING A DASHPOT AND A VENT CONTROL FOR SAIDDASHPOT; SAID VENT CONTROL COMPRISING A CASING DEFINING A FIRST CHAMBER,A PRIMARY VENT FORMED FROM SAID FIRST CHAMBER, A SECOND CHAMBER INCOMMUNICATION WITH SAID FIRST CHAMBER, A SECONDARY VENT FROMED FROM SAIDSECOND CHAMBER, AND A SLIDE VALVE DISPOSED IN SAID FIRST CHAMBER AND A